1. Field of the Invention
The invention relates to a control lever assembly, in particular to a twin lever control assembly for push-pull cable operated devices as used for controlling the throttle and clutch of a marine power unit.
2. Prior Art
Twin lever controls having clutch and throttle levers have been used for many years in marine vessels. With such controls an operator can control the clutch and throttle independently to enable safe and effective operation of the marine engine driving the propeller shaft through a gear box. The throttle lever controls the engine speed and can be positioned at any position between idle and full throttle so as to permit fine adjustment of engine speed. Commonly, a friction or drag device is used to prevent the lever accidentally creeping due to vibration that is commonly present on marine vessels. The clutch lever has three basic positions, namely ahead and astern and an intermediate position, neutral. Commonly, for safety, an indexing device is provided to locate the clutch lever in the neutral position so as to prevent accidental engagement of the gears. The two levers are mounted in a common housing on opposite sides thereof, and each lever is connected to one or two control cables, two cables allowing operation in series or in parallel rigging. The cables used are push-pull type control cables in which a core slides in a flexible sleeve which permits routing of the cable as desired, and provides positive action in tension or compression as the lever is swung in either direction.
The control levers are fitted at one or more control stations about the vessel and commonly there is a shortage of space at such stations and thus a relatively compact lever assembly is an advantage. Some prior art lever assemblies are relatively bulky and, when installed in the vessel, are difficult to connect to cables and also to service, and some of this difficulty results from the relatively large size of the control unit fitted in a small space. A common limitation to the size of the unit relates to the structure for anchoring ends of the control cables to the lever assembly. Commonly, an end of each cable core carries a clevis which is pinned to a bellcrank or other rotatable member controlled by the lever. The clevis is connected to the bellcrank by an axle pin which is commonly a bolt secured with locked nuts, cotter pin locking means or equivalents. For connection of the clevis to the lever, lateral clearance in the housing for insertion of the pin or bolt through the clevis is required. When two levers are fitted in the same housing a considerable amount of space is required for this connection otherwise servicing becomes very cumbersome. In the past, to reduce the space required, the design of such control levers has been compromised in order to take up less space, which increases the difficulty of servicing.
Also, the friction or drag means to prevent creeping of the throttle lever, and the indexing means to locate with the clutch lever in neutral have been particularly difficult to install in the space available and in some types have been incorporated into the same structure such that an adjustment of the throttle drag also tended to effect drag of the clutch lever and this detracted from "feel" of the clutch for locating neutral.